1. Field of the Invention
The invention relates to communications networks in general and in particular, to a device and a method for improving the reliability of broadcast data transmissions in such networks.
2. Prior Art
The proliferation of computers creates a need for more reliable and efficient communications networks to interconnect the computers. Prior art communications networks may be broadly classified into two types, namely; wired and wireless. Both types of communications networks provide the communications highway over which the computers or other attached devices exchange information.
In a wired communications network, the computers, terminals, workstations, etc., are interconnected via hardwired communications media. The communications media may include copper wire, fiber optics, etc. Also, the communications media and attached devices may be configured into a serial network, a star network, etc. Whether the network is configured as a serial star or any of the other known configurations depends, to a great extent, on the application to be practiced on the network.
In the wireless communications network, the attached devices are interconnected via wireless medium. The wireless medium may include radio frequency (RF), infrared light, etc. Like the wired communications networks, the wireless networks may be configured as a serial network, a star network or any of the other known configurations.
In addition to the physical structure, a protocol/architecture is required to ensure faithful delivery of the data between the interconnected devices. One of the conventional approaches is to assemble data into packets and "broadcast" the packets from one of the devices (called a controller) to other devices on the network. In the event that a packet is not received by a device, the device requests retransmission of the packet. U.S. Pat. No. 4,807,224 describes and shows a multicast data distribution system in which a data source assembles data and transmits the data through a communication node to a plurality of end users nodes. A device (called a recovery means) is connected to the communication node. The recovery means captures data which is transmitted from the data source and stores it in a ring buffer located in the recovery means. If an end user node does not receive a packet, it requests retransmission of the missing packet from the recovery means which provides the missing packet from its ring buffer or obtains it from the data source and retransmits it to the end user node.